more of a strong beliefs is not how college friends describe dzhokhar tsarnaev. these students who saw the friends deother not even three hoeks ago told us he was not the least bit religious and cared more for soccer, cars, and parties. >> how in the world did this bippen? >>pelley: george mcmasters hired dzhokhar as a 16-year-old hfeguard. >> how could he have been d.anged so much in the year, year and a half that i'd been absent, go from a young man that was polite, well spoken, friendly, engaging, typical american teenager to what i havy t i ha is a monster. >> reporter: mcmasters served in the national guard and, because he speaks arabic, he was assigned to guantanamo bay,ays t viewed detainees. ewedith my experience with other terrorists, you know, reflecting on it, i see how they get radicalized, how they can be drawn in, taken advantage by older men, older brothers, not only ruining their own life but becoming dangerous to the society. say thay: you say that you understand how these young men ite radicalized. explain it to me. tr when i would try to ask th